Utilizing an rfid tag in manufacturing for enhanced lifecycle management

ABSTRACT

Data associated with supply chain events for a manufactured assembly is automatically stored. In preferred embodiments the supply chain events for the manufactured assembly are stored on an RFID tag attached to the assembly as it travels through the supply chain to insure the data concerning the assembly is readily available and not separated from the assembly. In other embodiments, the supply chain events or characteristic data is stored on the RFID tag in a hierarchical structure beginning with the original state of the assembly and with additional entries for each step in the assembly process. In other embodiments, as the product undergoes rework, conversion to a different assembly, or personalizations, the new state of the assembly is stored in the RFID tag. In other preferred embodiments, other information is also stored on the RFID tag such as country of origin, failure data, cycle times and a quality status indicator.

CROSS-REFERENCE TO PARENT APPLICATION

This patent application is a continuation of U.S. Ser. No. 11/360,348filed on Feb. 23, 2006, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention generally relates to RFID tags, and more specificallyrelates to utilizing an RFID tag in a manufacturing environment and animproved method and apparatus to store historical data on the RFID tag.

2. Background Art

Through strategic product outsourcing, manufacturers continue to drivemore and more manufacturing and product content to vendors thatspecialize in certain technologies. This product outsourcing allowsprimary manufacturers to specialize in technologies that provide themost value added content to their customers. A manufactured assembly mayconsist of multiple levels of assemblies and part numbers produced byseveral vendors in the chain of producing the assembly. Further, due toerrors in supply/demand planning, order skew, configuration variability,as well as product defects, a manufacturer may need to change orre-personalize many of the purchased assemblies. In order tore-personalize or re-configure the assemblies it is important for themanufacturer to know exactly the current state as well as the history ofthe assembly.

Manufacturers may require its vendors to create a hierarchal datastructure of the assemblies and supply the data to the manufacturer. Thedata is typically placed in a database. The data can then be used toreconfigure the product assemblies and the database updated to reflectthe reconfiguration. This solution is costly and the product identity ofprevious sub-assemblies can be lost due to product reconfiguration. Ifan item is returned to the original vendor, there may be no originalpart number identification on the assembly for the vendor to verify itsown assembly, which may require the manufacturer to search its recordsto prove the vendor is the original manufacturer of the assembly.

RFID tags are commonly used in the manufacturing industry to track andidentify goods throughout the manufacturing process and for shipment tocustomers. RFID tags are similarly used by the end retailers. However,when RFID tags have been utilized in the manufacturing process, theyhave been used to only record “point in time” data, or the currentstatus of the assembly. FIG. 2 shows a data record 200 for a prior artRFID tag. The data record shows the current state of the assembly byshowing the part number 210, serial number 220 and other content 230.The information stored on the typical RFID tag as shown in FIG. 2 doesnot record the historical activities performed on the assembly andhierarchal information of the assembly such as the changing part number.This additional information is typically supplied to the manufacturer ina database format from the various vendors as described above.

Without a way to manage the history of a manufactured assembly in acomplex supply chain, manufacturers will continue to bear the high costsof maintaining data from multiple vendors and other costs associatedwith re-configuring product assemblies.

DISCLOSURE OF INVENTION

The preferred embodiments herein describe a method and apparatus tostore the supply chain events for a manufactured assembly. In preferredembodiments the supply chain events for the manufactured assembly arestored on an RFID tag attached to the assembly as it travels through thesupply chain to insure the data concerning the assembly is readilyavailable and not separated from the assembly.

In other preferred embodiments, the supply chain events orcharacteristic data is stored on the RFID tag in a hierarchicalstructure such as a dynamically linked list, where data is storedbeginning with the original state of the assembly and additional entriesare added for each step in the assembly process. In other embodiments,as the product undergoes rework, conversion to a different assembly, orpersonalizations, the new state of the assembly is stored in the RFIDtag in addition to previously-stored information. In other preferredembodiments, other information is also stored on the RFID tag such ascountry of origin, failure data, cycle times and a quality statusindicator.

The foregoing and other features and advantages of the invention will beapparent from the following more particular description of preferredembodiments of the invention, as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

The preferred embodiments of the present invention will hereinafter bedescribed in conjunction with the appended drawings, where likedesignations denote like elements, and:

FIG. 1 is a block diagram of an RFID Tag used with an RFID tag readeraccording to preferred embodiments;

FIG. 2 is another system block diagram of RFID tag data according to theprior art;

FIG. 3 is a table of data representing an as built history according topreferred embodiments;

FIG. 4 is a table of data representing an as built history according topreferred embodiments;

FIG. 5 is a table of data representing an as built history according topreferred embodiments;

FIG. 6 is a block diagram of a dynamically linked list for storing an asbuilt history according to preferred embodiments;

FIG. 7 is a block diagram of an RFID chip according to preferredembodiments;

FIG. 8 method diagram for storing an as built history according topreferred embodiments; and

FIG. 9 method diagram for storing an as built history according to otherpreferred embodiments.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to an apparatus and method to utilize anRFID tag in manufacturing. FIG. 1 shows a block diagram that representsan RFID tag in a manufacturing environment according to preferredembodiments herein. An RFID reader 110 communicates with a manufacturedassembly 120 with an RFID signal 130 to an RFID tag 140 located on theassembly 120. The RFID tag 140 includes an antenna 142 to receive theRFID signal 130 to activate and communicate with the RFID chip 144. Inpreferred embodiments, the RFID chip 144 includes a quality statusindicator 146 and an as built history 148 to store data associated withsupply chain or manufacturing events to create a hierarchical history ofthe manufactured assembly 120. A manufacturing event is recorded foreach significant change in the status of the assembly, such as adding anew sub-assembly or performing a manufacturing step on the assembly.

Again referring to FIG. 1, the quality status parameters 146 are similarto manufacturing events, but are specifically used to indicate qualitycontrol parameters of the assembly. In preferred embodiments, thequality status parameters includes a usability indicator to indicate anoverall good/bad status of the part. Data associated with the usabilityindicator can give specific information about the quality issues for theassembly. The usability indicator, and other quality control parametersare used to quickly determine the status of the assembly to controlmovement and disposition of the assembly through the manufacturingprocess. This feature of the preferred embodiments embeds the usabilityof an assembly with the RFID tag attached to the assembly to insure thestatus is not lost with assembly paperwork. Further the quality statusparameters can be easily passed between vendors in the supply chain.

According to preferred embodiments, supply chain events for amanufactured assembly are stored on the RFID tag 140 attached to theassembly as it travels through the supply chain to insure the dataconcerning the assembly is readily available and not separated from theassembly. FIGS. 3-5 illustrate an example of an as built history 148shown in FIG. 1 according to a preferred embodiment. In this example,the as built history is represented as a table 300 of data that isstored on the RFID chip 144. In this example, the as built history table300 includes a vendor ID 310, part number 320, serial number 330,data/time 340 and content of the history entry 350. Each entry 360, 362,364, 366, 368 of the table is data for a unique manufacturing event. Thecontent of the history entry contains other data associated with theassembly for the manufacturing event. This other data could include thecountry of origin, the part cost, a commodity code, revision of embeddedcode, part description, etc.

Again referring to FIG. 3, when a first assembly or subassembly is builtan RFID tag is attached to the assembly by the vendor. The as builthistory table 300 in the RFID tag is initially loaded by the firstvendor in the supply chain to start the as built history of theassembly. The first vendor (Vendor A) records data in the first entry260 in the table 300 as shown in FIG. 3. In this embodiment, when avendor makes changes or additions to an assembly, all the data in thetable 300 is read and stored in the RF reader 110 (FIG. 1), new data isappended to the read data and then the combined data is loaded into thetable. This read and then re-write process is necessary when the RFIDtag has a flash memory that is written to as a single block. Thus, inthe illustrated example, Vendor B reads the data in the first record260, concatenates data for a new entry, and stores the data into the asbuilt history 300. The table 300 then has the first entry 260 restoredback into the first position in the table, as well as the new secondentry 262 stored in the second position as shown in FIG. 4. In thismanner the supply chain events are stored on the RFID tag in ahierarchical structure beginning with the original state of the assemblyand with additional entries for each step in the assembly process. Anexample of a completed table 300 of data for an assembly is representedin FIG. 5 which has three additional entries 364, 366, 368. The partnumber and serial number of the entries change to reflect the changingnature of the assembly as sub-assemblies are added and manufacturingsteps are applied to the assembly.

The method described with reference to FIGS. 3-5 requires each vendorapplication accessing the data on the RFID tag to concatenate any newdata with previous data storing the concatenated data back into the asbuilt history table 300. This embodiment solves some of the problemsdescribed with reference to the prior art, but it requires that eachsupplier's application concatenate and reload the data. Further, thismethod does not ensure the integrity of the hierarchal history will bemaintained as described in the embodiments described below.

FIG. 6 illustrates a linked list data structure 600 to store the asbuilt history 148 (FIG. 1) according to other preferred embodiments.When a vendor makes changes or additions to an assembly, the data in theRFID chip 144 can be read for reference, but any existing data is notmodified, and new data is appended to the existing data using the linkedlist 600. The linked list has multiple records 610 that each have aprevious link 620, a next link 630 and a data field 640. The previouslink 620 a of the first record 610 a and the next link 630 n of the lastrecord 610 n are coded as a null link to indicate the beginning and endof the linked list respectively. The data field 640 of each record 610is loaded with the data of a single entry in the as built history table300 as described above with reference to FIGS. 3-5. For example, thedata field 640 a in the first record 610 a is loaded with the data shownin first data entry 360 in FIG. 5 and the second data field 610 b isloaded with the data shown in the second data entry 362. The other datafields are loaded in a similar manner so that the linked list containsthe data in a hierarchal structure based on the sequence the recordswere added to the linked list by one or more vendors.

FIG. 7 illustrates an RFID chip 144 to implement the linked listdescribed in FIG. 6 according to a preferred embodiment. The RFID chip144 includes a micro-controller 710 to process commands from the RFIDreader (110 FIG. 1). The micro-controller is a low power, smallinstruction set micro-controller or state machine that gives the RFIDcontroller a limited processing capability to respond to commands fromthe RFID reader. The commands instruct the RFID chip to manage thedynamic linked list described above to allow the reader to selectivelywrite records to the linked list rather than writing the whole as builthistory at once in the manner described in the previous embodiment. Thecommands to manage the linked list are similar to those commands knownin the prior art to access a linked list. Some basic commands includeinitialize the data storage, add data to head of the list, read headnode, read a node at a list location, and clear the list.

FIG. 8 shows a method 800 for storing an “as built history” according topreferred embodiments herein. If the RFID tag is a new tag being placedon a new first assembly (step 810=yes) then the initial vendorinformation and assembly information is stored on the RFID tag attachedto the assembly (step 820). The RFID tag need not be directly attachedto the assembly but is associated with the assembly, such as attached tothe packaging. If the RFID tag is not a new tag (step 810=no) then thecomplete as built history stored on the RFID tag is read into the RFIDreader (step 830). The new manufacturing event is concatenated with theas built history read from the RFID tag (step 840) and the concatenatedas built history is stored to the RFID tag attached to the assembly(step 850). The method is then done.

FIG. 9 shows another method 900 for storing an “as built history”according to preferred embodiments herein. If the RFID tag is a new tagbeing placed on a new first assembly (step 910=yes) then a linked listis initialized on the RFID tag attached to the assembly and the initialvendor information and assembly information is stored in the linked list(step 920). The RFID tag need not be directly attached to the assemblybut is associated with the assembly, such as attached to the packaging.If the RFID tag is not a new tag (step 910=no) then an append command issent to the RFID tag with the new manufacturing event data to place inthe as built history (step 930). The RFID micro-controller determinesthe next position in the linked list (step 940) and new data is storedin the next position of the linked list of the built history on the RFIDtag attached to the assembly (step 950). The method is then done.

As described above, embodiments provide a method and apparatus to storethe supply chain events for a manufactured assembly. In preferredembodiments the supply chain events for the manufactured assembly arestored on an RFID tag attached to the assembly as it travels through thesupply chain to insure the data concerning the assembly is readilyavailable and not separated from the assembly. The method and apparatusdescribed herein provide a way to manage the history of a manufacturedassembly in a complex supply chain to reduce the costs of maintainingdata from multiple vendors and other costs associated withre-configuring product assemblies.

One skilled in the art will appreciate that many variations are possiblewithin the scope of the present invention. Thus, while the invention hasbeen particularly shown and described with reference to preferredembodiments thereof, it will be understood by those skilled in the artthat these and other changes in form and details may be made thereinwithout departing from the spirit and scope of the invention.

1. An RFID tag associated with a manufactured assembly comprising: anantenna; an RFID chip connected to the antenna to receive acommunication signal from an RFID reader; an as built history stored onthe RFID chip that includes a plurality of manufacturing events for aplurality of sub-assemblies that comprise the manufactured assembly;wherein the plurality of manufacturing events are arranged in a timebased hierarchy; wherein the RFID tag comprises a micro-controller tocontrol commands received from the RFID reader to store the plurality ofmanufacturing events in the dynamically linked list; and wherein theplurality of manufacturing events include a vendor ID, a part number, aserial number, a date and time, and at least one quality statusparameter includes a good/no good indication of the usability of theassembly. 2.-7. (canceled)
 8. An RFID tag associated with a manufacturedassembly comprising: an antenna; an RFID chip connected to the antennato receive a communication signal from an RFID reader; amicro-controller to manage commands received from the RFID reader; an asbuilt history stored on the RFID chip that includes a plurality ofmanufacturing events for a plurality of sub-assemblies that comprise themanufactured assembly stored in a dynamically linked list in response tothe commands from the RFID reader; wherein the plurality ofmanufacturing events are arranged in a time based hierarchy; wherein theplurality of manufacturing events include a vendor ID, a part number, aserial number, a date and time, and at least one quality statusparameter includes a good/no good indication of the usability of theassembly; and wherein a first manufacturing event is stored by a firstvendor and a second manufacturing event is stored by a second vendorduring the manufacturing process of the manufactured assembly. 9-13.(canceled)